Chelsea can deliver a knockout blow to Arsenal's Premiership hopes on Sunday, says midfielder Michael Ballack.
"I think it's very difficult for Arsenal to come back into the title race," said Ballack. "Already they see a big gap between them and us. When you are on top of the league it's up to other teams to chase and close the gap.
"When you play against a big team, sometimes a point is enough because you retain the gap between you and them.
"It's not always the games between the big four which decide the title.
"There are games when all the big clubs lose unexpectedly. You can win five or six games in a row even when you are chasing.
"But when it comes to facing your big rival, when you're behind, that's when the pressure is there to win, not on the team that is on top already.
"At the moment we're on top, Arsenal are 10 points behind us, so they have to win."